Hi,
I’ve been doing pulse based training for more than a decade (mostly running and xc-skiing), but just quite recently started to use training load/TSS (the calculated value) as an estimation of the traning load (actual). In general I really like the idea of how it simplifies planning and analysis. However, what I find hard to understand is why the load/TSS is overestimated for longer easy sessions compared to shorter more intense sessions. Example: The load value of an easy session of 4 hours (RPE 3) is about 120, which then is much higher than an interval session of 30 minutes well above FTP (RPE 9) giving a load of about 60. Looking at the numbers the long session “stresses” the body twice as much! From experience this is not true for me at least. The long session would empty your glycogen store but other than that you would be fit for fight the next day. The hard session would probably require at least one easy day to recover. Can anyone with better insight elaborate on this?
As a side note. I’ve compared calculated values of training load based on power, HR and RPE. And normally they match quite nicely so I think load values are ok and my power/HR zones etc are correct.
This attempts to compensate intensity vs time to be equal but as you’ve noticed does not do this perfectly. Not all TSS is equal. Its substantially better than tracking hours/session or week or average power/session but clearly has its short comings. Depending on goals, sport, discipline within that sport the other metrics used along with TSS and the “value” you should give to TSS alone will vary. Example: A criterium racer can likely have a significantly lower TSS over a week than a climber. However the crit racer is going to likely have a lot more time in the upper zones and even within workouts have more intervals and therefore repeatability. The climber is going to have a lot of time in the middle/lower zones but likely a lot less intervals per a given work out. All that to say TSS is just one part of tracking your training and should be taken in context of the rest of training.
Very comprehensible answer!
To illustrate even more I would add that a 5hour long ride for a crit racer will probably yield a TSS that is ‘underestimated’ because his body is not accustomed to that kind of effort while a GC rider might consider the TSS for that same ride as ‘overestimated’. The same would be true, but the other way around for a HIT with anaerobic intervals.
TSS works well for ‘middle ground’ but needs to be evaluated for ‘specialism’.
If anything, in my experience, TSS is underestimated for the harder VO2 max rather than overestimated for the base work.
That’s it’s one major flaw imo that it doesn’t really capture the difficulty of a VO2 max session. There’s a great correlation between fitness and TSS during winter base training but not so much when intensity ramps up
Thanks for the input guys! Your reasoning gives some perspective. I guess just using the TSS/TL value alone is making it too easy. And I agree with @nasatt that it’s rather an underestimation of VO2 max sessions than an overestimation of easier work. I mean, if you consider what happens physiologically when you pass FTP and transition into the VO2 max region, there is an obvious non-linearity (a “break in the curve”). This is not something you can predict by using the TSS power formula. It is approximately linear around FTP (and any other power). Quite interesting though is that the TSS vs RPE table suggested by TP shows a break:
The way I understand it is that TSS/TL can be a good measure/predictor between training blocks as long as the blocks have similar constitution of volume and intensity. And that changing both these parameters at the same time too much from one block to the next requires more than just a TSS value comparison.
I hear this a lot, and while TSS is not a perfect metric, you are comparing apples with oranges.
A 4hr low intensity session creates a bigger load than a 1hr session with 20min of VO2max in it. Its not representing the difficulty of the session. VO2max sessions hurt like hell, but you could repeat that day after day if you wanted to because the load of the session is not that high.
Intensity Factor represents how intense or hard the session is, TSS represents the impact of the session.
TSS does not consider work you have done previously. Without knowing more about what you have done before, there is a possibility your ride felt harder, because of the run the day before. However feelings on there own are unreliable. If you did, for instance, a massive ride in the morning, and a 30-min low intensity run in the afternoon, I expect the run will feel much harder than it the same run on fresh legs. The load is the same, its the accumulation of TSS that is creating load. Thats where metrics like form or TSB are relevant and the other one i use a lot is Acute/Chronic Load ratio.
I would not get bogged down in comparing run and ride loads though, as they are different. Stryd or no Stryd.
I think someone else said it above, TSS is a guide, there is lots it doesnt know. If you completed a session but were massively underfuelled and hanging on, it will give the same score as performing the ride well fuelled. The impact of finishing in a depleted state will have a knock on effect. Compound that by under fuelling recovery and the following day is going to get really emotional! TSS doesnt know that nor do any of the other metrics.
Loads can be very similar for cycling and running, on the condition that both disciplines have a fairly correct FTP. And that FTP can be really different in between running and cycling. For cycling in general it doesn’t matter what equipment you’re using, all real power meters give you something that is accurate enough in the same small range.
For running, on the contrary, power is the result of an algorithm. It’s not a direct power measurement. There are huge differences in between different devices, and no one can tell which one is the most correct. If you search on the forum, you will see that other users reported big differences in between Garmin wrist power and Stryd.
If your FTP for running is underestimated and from cycling overestimated, load for a seemingly equal stressing workout will be very different and so will feel.
I don’t agree. If you were able to do VO2max sessions every day given the relative low load that would be the recommended programming for anyone with a limited time for training. On the other hand daily 1-2 hours of low intensity distance sessions (with equal or higher TSS) you see a lot. Even if you have a relative low volume of say 6-8 h/week, 80/20 is a good rule of thumb.
Thats not really the point of TSS, its just a strain. It doesn’t describe the type of strain. You are getting into specificity and planning. Using only TSS is a recipe for disaster.
80/20 training is completely different conversation. There also good evidence to suggest other training works better, depending upon the aims and strengths of the individual. I see many long course triathletes sold on 80/20 who train really well but can’t do a race. 80/20 has nothing for them at race intensity.
If you are doing 10hr a week can you really do 2hr over FTP? If you are doing 16hrs thats 3.2hr - nonsense. The literature shows that in endurance athletes if you are going to polarise its more like 90/10 %time. - However this is nothing to do with TSS
Yes I’m well aware of that 90/10 is more common for higher volumes. The point is that 90/10 (or 80/20) means that you need adequate rest between high intensity sessions, and that volume comes from low intensity sessions, which you can do ALOT of. Doing VO2max sessions every day is a recipe for disaster. On the other hand, daily LSD sessions is the norm for serious endurance athletes. So again, how does the easy sessions ”load/impact/strain” your body more than the hard sessions?
So again, how does the easy sessions ”load/impact/strain” your body more than the hard sessions?
From your previous post, 1-2 hours of low intensity is not enough to get the adaptations, and fatigue, from riding for 5-8 hours.
A 5-hour ride is bound to give you as much fatigue as a shorter session with VO2max power.
Volume is made up of Duration & Frequency
Intensity is how hard or easy the session is.
Yes doing a VO2 session every day is not the best plan for training adaptation, you need a varied programme. Volume is not rest though. An easy session is a short low intenisty one. Low intensity does not mean easy though.
